Update README.md

[tolyod]

git@github.com:mokevnin/dotfiles.git scheme does not always work

[mokevnin]

Could you add more details? What cases do you have in mind?

[tolyod]

this command does not work on a fresh installation of Ubuntu.
but git clone https://... works

[fey]

@tolyod you should set up ssh key and agent for git
https://docs.github.com/en/authentication/connecting-to-github-with-ssh/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent